38 C.F.R. § 19.23
Applicability of provisions concerning Notice of Disagreement
(a) Appeals governed by § 19.21(a) shall be processed in accordance with § 19.24. Sections 19.26 and 19.28 shall not apply to appeals governed by § 19.21(a).
(b) Appeals governed by § 19.21(b) shall be processed in accordance with §§ 19.26 and 19.28.